Shrouded drum skimmer

ABSTRACT

A drum-type skimmer for separating a surface layer of material from a body of liquid comprising a rotating drum disposed for partial submersion within the liquid and a shroud with a depending baffle positioned radially from and adjacent to the lower portion of the drum to improve the skimming action between the drum and the material to be skimmed.

United States Patent Tillett et al. [451 Sept. 26, 1972 SHROUDED DRUM SKIMMER 3,536,199 10/1970 Cornelius ..210/D1G. 21 [72] Inventors: Thomas J. Tillett, Ambler; Barry ichambealger Straus, Lansdale, both of Pa. osar et a [73] Assignee: FMC Corporation, San Jose, Calif. Primary Examiner-John Adee Filed: April 1970 Att0rney-F. W. Anderson and C. E. Tripp [21] Appl. No.: 30,734 RACT A drum-type skimmer for separating a surface layer of material from a body of liquid comprising a rotating h izgi 5; drum disposed for partial submersion within the liquid and a shroud with a depending baffle positioned radi- [58] Fleld of Search ..210/396, 319, 520, 523, DIG. ny from and adjacent to h lower p i of the 21 drum to improve the skimming action between the v drum and the material to be skimmed. [56] References Cited 1 UNITED STATES PATENTS 2 Claims, 2 Drawing Figures 3,429,446 2/1969 Vorderbrugge. ..2l0/396 PATENTEDSE-Pz I912 3 Q 693; 8 0s Fl 6. 2 I INVENTORS THOMAS J. TILLETT BARRY STRAUS ATTORNEYS SHROUDED DRUM SKIMMER BACKGROUND or THE INVENTION The present invention relates to apparatus for separating a surface layer material from a liquid. For example, the apparatus may be employed for separating liquids of different polar characteristics, such as for removing oil substances from the top surface of water or the like in waste disposal plants.

More particularly, the apparatus relates to a rotatable drum skimmer adapted to pick up a liquid of a first polar characteristic, such as oil, floating over a second liquid of a second polar characteristic, such as water. I-Ieretofore, there have been various apparatus for skimming utilizingrotating drums for separating oil from another liquid in which the cohesive characteristics between the oil and the drum surface in relation to the cohesive characteristics of thedrum surface and a second liquid overwhich the oil appears are employed. Available structures frequently call for a drum submerged within the mixture beneath the lower level of the oil. The outer surface of the drum is selected to cohere to the oil. Thus, as the drum is rotated, the oil is raised with the drum surface and separated from the other liquid. An oil scrapper blade or other means is positioned above the surface level to remove the oil from the drum surface. The removed oil is then collected in separate container means, such as drums or the like. Prior art structures utilizing these or similar concepts are illustrated and describedin U.S. Pat. No. 1,860,819; U.S. Pat. No. 3,358,838 and U.S. Pat. No. 3,259,245.

SUMMARY OF THE INVENTION The present invention relates to a drum-type skimmer for separating substances of different polar characteristics with greater efficiency. Toward this end, a shroud is disposed radially from the lower portion of a submerged drum so as to increase the cohesive action between the substance to be removed and the surface of the partially submerged drum.

In an exemplary embodiment of the present invention, an arcuate shroud defining approximately a ninety degree are is secured radially from and adjacent to the lower portion of the peripheral surface of the drum. The shroud is positioned so as to be disposed below the liquid level and to extend above the liquid level. The radial spacing between the shroud and the outer surface of the drum is selected for an effective cohesive action between the liquid to be skimmed and the outer surface of the drum. By means of the shroud, an improved cohesive action is built up between the drum surface and the substance to be skimmed by means of the drum surface.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, diagrammatic side elevational view, partially in section of a sewage disposal plant skimmer apparatus embodying the present invention.

FIG. 2 is a perspective view of a shroud baffle assembly for the skimmer apparatus shown in FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENT Illustrated in FIG. 1 is a drum-type skimming apparatus l0 embodying the present invention. The ap' paratus 10 is adapted for use in a waste disposal facility for removing hydrophobic substances, such as oil 11, from water 12 or other liquid material having polar characteristics differing from that of the oil. The apparatus 10 is supported within a large vat 13 containing waste and comprises a drum l4 rotatable about a central axis 15. The drum 14 is suitably driven by a drive means that includes a driven pulley 16 fixed to a drive shaft 18. An endless belt 20 is trained around the pulley 16 and is also trained around a pulley 21. A drive assembly including a drive motor 22 is coupled to a speed reducer 24 through a coupler 26, which speed reducer 24 rotates a shaft 27 to impart rotation tothe driver pulley 21. The motor 22 and speed reducer 24 are supported upon a support assembly 28 whichalso supports the shaft 18 for rotation at a bearing block 30.

Adjacent the upper portion of the drum 14 is an oil scraper assembly 32 for removing oil from the-surface of thevexposed surface of the drum 14 before the exposed surface of the drum is again submerged in the liquid. The scraper assembly 32 has an edge 34 for abutting the outer peripheral surface of the drum 14. The scraper 32 forms a trough 36 extending from the edge 34 to an oil conduit 38 or other oil container means. The oil conduit 38 is secured in place to the support assembly 28 by an angle arm 39 and is adapted to provide a channel for the removed oil to an exterior collector, such as oil drums or the like.

The drum 14 in FIGS. 1 and 2 maybe viewed as comprising four quadrants. Adjacent to and spaced from the lower portion of the outer periphery of the drum within the fourth quadrant is an arcuate shroud 40 having a longitudinal center line coincident with the axis of the shaft 18 and the axis 15. The shroud 40 is fixed by a clamp 41 to the support structure 28 and is positioned radially from the surface of the drum 14 within the fourth quadrant to establish a uniform spacing 42 intermediate the outer surface of the drum 14 and the inner surface of the shroud 40 adjacent to the drum 14 on the upward path of the drum beneath the liquid level. The drum 14 rotates in the direction of the arrow 43 (FIG. 1) and defines an arcuate surface of ninety degrees in the exemplary embodiment. The spacing 42 extends from the lowest point of the drum 14 within the vat 13 to a point above the surface level of the sewage. At the submerged end of the shroud 40 is a baffle 44 extending laterally from the substantially normal to the end of the shroud 40 or radial from the drum 14. The baffle 44 extends the full longitudinal length of the shroud 42 and serves as a header decreasing the velocity of the liquid relative to that of the drum 14.

The shroud 40 comprises a pair of semicylindrical laterally extending end plates or discs which are disposed to have a center line coincident with the axis of the shaft 18. The end discs 46 and 48 are formed with end joumaling members 50 and 52, respectively, adapted to receive the ends of the shaft 18. Intermediate the end plates 46 and 48 is an arcuate member 54 of substantially one-fourth of a cylinder centrally aligned with the end plates and extending over approximately one-half of the outer edge of the end plates 46 and 48.

In operation, it has been found that the shroud 40 tends to create an effective layer build-up of the oil 11 against the drum 14 peripheral surface. The oil tends to adhere to the drum surface on the up-swing path of the drum, whereas with prior art structures the oil has been found to lose contact on the up-swing portion of travel. It appears that the shroud precludes the drum from being wetted by the water once the drum passes below the oil strata level in the tank and an oil film is maintained at all times until removed by the scraper blade 34. Consequently, more oil 11 is delivered to the scraper assembly 32 and the overall oil pumping efficiency is improved.

What I claim is:

1'. Apparatus for separating from a liquid substances of differing polar characteristics comprising, in combination; a drum rotatable about an axis of rotation, said drumbeing partially submerged within the liquid with'a portion thereof disposed above the surface level of the liquid; a fixed positioned shroud disposed adjacent to and radially from a portion of the peripheral surface of the drum and spacedvtherefrom to form a confined passageway between the drum and the shroud, the passageway beginning at a first end of said shroud beneath the surface level of the liquid and ending at a second end of said shroud above the surface level of the liquid, said drum being rotatable in a direction to sweep from said first end of said shroud toward the second end of said shroud, said shroud extending longitudinally relative to said drum and having a central axis disposed parallel with the axis of rotation for said drum, said shroud being symmetrical about its centerline and forming an arcuate member positioned adjacent to the peripheral surface of said drum, whereby the upward path of travel of said drum below the level of the liquid sweeps past said shroud, said shroud further including confronting semi-cylindrical end plates at the opposite ends of said arcuate member, said arcuate member defining an arcuate surface of ninety degrees; and a baffle member extending laterally from said shroud adjacent to the first end thereof, said baffle member extending substantially the full longitudinal length of said shroud, said baffle member further extending from said shroud member in a direction radially away from said drum.

2. Apparatus for skimming off a layer of material such as oil or the like floating on the surface of a heavier body of liquid such as water, said apparatus being of the type comprising a rotating drum partially immersed in the liquid with means above the surface of the liquid for scraping off floating material picked up by the drum; the improvement comprising a shroud fixed adjacent to a portion of the peripheral surface of the drum, said shroud including an arcuate member that is radially spaced from but adjacent to the periphery of the drum to form a confined passageway between the drum and the arcuate member, saidarcuate member extending longitudinally of the drum with its central axis parallel to the axis of drum rotation, said arcuate member defining an arcuate surface having an extent of not substantially less than ninety degrees, said arcuate member having a lower end positioned beneath the surface of the liquid and having an upper end positioned above the surface level of the liquid, said confined passa eway beginning at the lower end of said arcuate mem r and ending at the upper end thereof, means for rotating said drum in a direction to sweep said separated material upwardly from the lower end of said arcuate member toward the upper end thereof and through said confined passageway, said drum carrying said separated material above the surface level of the liquid, said shroud including confronting end plates at the opposite ends of said arcuate member which end plates encompass the lower portions of the ends of said drum, said shroud including a baffle member extending substantially the full length of said arcuate member and projecting from adjacent said lower end of the arcuate member in a direction radially away from the drum. 

1. Apparatus for separating from a liquid substances of differing polar characteristics comprising, in combination; a drum rotatable about an axis of rotation, said drum being partially submerged within the liquid with a portion thereof disposed above the surface level of the liquid; a fixed positioned shroud disposed adjacent to and radially from a portion of the peripheral surface of the drum and spaced therefrom to form a confined passageway between the drum and the shroud, the passageway beginning at a first end of said shroud beneath the surface level of the liquid and ending at a second end of said shroud above the surface level of the liquid, said drum being rotatable in a direction to sweep from said first end of said shroud toward the second end of said shroud, said shroud extending longitudinally relative to said drum and having a central axis disposed parallel with the axis of rotation for said drum, said shroud being symmetrical about its centerline and forming an arcuate member positioned adjacent to the peripheral surface of said drum, whereby the upward path of travel of said drum below the level of the liquid sweeps past said shroud, said shroud further including confronting semi-cylindrical end plates at the opposite ends of said arcuate member, said arcuate member defining an arcuate surface of ninety degrees; and a baffle member extending laterally from said shroud adjacent to the first end thereof, said baffle member extending substantially the full longitudinal length of said shroud, said baffle member further extending from said shroud member in a direction radially away from said drum.
 2. Apparatus for skimming off a layer of material such as oil or the like floating on the surface of a heavier body of liquid such as water, said apparatus being of the type comprising a rotating drum partially immersed in the liquid with means above the surface of the liquid for scraping off floating material picked up by the drum; the improvement comprising a shroud fixed adjacent to a portion of the peripheral surface of the drum, said shroud including an arcuate member that is radially spaced from but adjacent to the periphery of the drum to form a confined passageway between the drum and the arcuate member, said arcuate member extending longitudinally of the drum with its central axis parallel to the axis of drum rotation, said arcuate member defining an arcuate surface having an extent of not substantially less than ninety degrees, said arcuate member having a lower end positioned beneath the surface of the liquid and having an upper end positioned above the surface level of the liquid, said confined passageway beginning at the lower end of said arcuate member and ending at the upper end thereof, means for rotating said drum in a direction to sweep said separated material upwardly from the lower end of said arcuate member toward the upper end thereof and through said confined passageway, said drum carrying said separated material above the surface level of the liquid, said shroud including confronting end plates at the opposite ends of said arcuate member which end plates encompass the lower portions of the ends of said drum, said shroud including a baffle member extending substantially the full length of said arcuate member and projecting from adjacent said lower end of the arcuate member in a direction radially away from the drum. 